It is known in the art to produce low molecular weight unsaturated polyesters and copolyesters from fumaric acid, maleic acid, or maleic anhydride with 1,3- or 1,4-cyclohexanedimethanol. These low molecular weight materials generally find use as a part of a multicomponent coating or thermoset molding formulation. These polyesters and copolyesters have molecular weights too low to be useful for the manufacture of shaped objects without the presence of other polymeric or monomeric substances. U.S. Pat. Nos. 3,674,727, 3,730,808, and 4,195,102 contain examples of such polyesters. We are aware of no prior art which discloses the preparation of linear, high molecular weight, unsaturated polyesters from fumaric acid, maleic acid, or maleic anhydride with 1,3- or 1,4-cyclohexanedimethanol.
Conventional low molecular weight unsaturated polyesters are used for copolymerization with styrene or other vinyl monomers, or for coatings which are applied to substrates as low viscosity solutions and then are thermoset by various processes. Such low molecular weight unsaturated polyesters are not suitable for use as molding compositions. Because the unsaturated polyesters according to this invention are high molecular weight, moldable compositions (as opposed to solvent systems) can be obtained. Such high molecular weight unsaturated polyester compositions result in improved physical properties such as higher tensile strength, greater impact resistance, etc., in the products produced therefrom.